The present invention relates to a suspension arrangement for anode bars in cells for the electrolytic production of aluminum. A cell for producing aluminum electrolytically includes a flat steel shell with a carbon lining on the inside. The carbon lining forms the cathode, while the anode, which is also made of carbon, usually in the form of several carbon blocks or elements, fixedly held by anode hangers. The anode hangers are securely attached to an anode bar, providing a firm mechanical as well as electrical connection with the anode bar. Such carbon blocks are usually referred to as anode carbon bodies.
During the electrolytic process the carbon bodies are consumed at their lower ends by the precipitated gases, and to be able to keep a constant distance between the anode and the cathode, the anode bar and the anode carbon bodies have to be simultaneously lowered. The anode bar is provided with vertical regulating means, and when the anode bar has reached the lowermost regulating level, all the anode hangers are removed from the anode bar and temporarily attached to a so-called "crossing bar". The anode bar is then raised to its uppermost positions, whereafter all the anode hangers are reattached to the anode bar in its new position.
In a modern electrolytic cell of up to 250K. ampere, the weight of the anode suspension arrangement may be about 35 tons and the length of the anode bar about 11 meters. Obviously, with such dimensions, the anode suspension arrangement is a large and expensive construction.
The vertical regulating means for the anode bar has to be so constructed that the anode bar may be raised or lowered by parallel movement, or tilted to either end in its longitudinal direction to achieve an inclined position.
The known types of suspension arrangements may roughly be divided into three different groups.
A. Four separate jack devices, of which two at a time are driven by the same motor, are each mounted at one of the end corners of the anode bar. The jack devices are placed on or suspended by separate contruction elements which either stand at the short end of the electrolytic cell or on a self-supported anode superstructure. (If one, instead of two motors are used, it is not possible to tilt the anode bar.)
B. Separate jack devices are each driven by a motor. The jack devices are mounted on a hall floor on the center line of the electrolytic cell, at the short end of the cell, providing an upward movement of the anode bar.
C. One single jack device with a motor is mounted at one of the anode superstructure ends. The jack device controls two mechanisms (one on each side of the anode superstructure, and each attached to one of the beams of which the anode bar is made) and functions as follows: when the jack is moved upwards or downwards, the anode bar is subject to a sheer vertical movement (it is not possible to tilt the anode bar).
These existing arrangements have several disadvantages.
Arrangement A fulfils all functional demands, but when the electrolytic cells are very long, the mechanical load on the anode bar is favorable, which again results in the anode bar being too heavy if deformation stability is to be held within reasonable limits.
Arrangement B is encumbered with the same disadvantage as arrangement A and also must be provided with a sideway support for the anode bar.
Arrangement C provides a favorable location of the suspension points between the anode bar and the mechanisms, so that the mechanical dimensioning of the anode bar may be optimized, but lacks the possibility of lifting the anode bar which is commonly used in connection with the terminations (killing) of anode effect.